1. Field of the Invention
This invention relates to the field of mass air flow sensors and in particular to a production line test apparatus for conditioning air flow.
2. Prior Art
As part of the normal development process and ongoing quality control, mass air flow sensors must be environmentally flow tested. To environmentally flow test a mass air flow sensor, it is placed in an environmental chamber which controls humidity, temperature and pressure, and then conditioned air is flowed through it. In order to maintain a uniform temperature distribution inside the environmental chamber, fans move and mix the air inside. This mixing action leads to a non-uniform air flow profile at the inlet to the mass air flow sensor, seriously degrading its test performance.
It is known to attempt to straighten air flow by using a bell mouth intake inlet to the mass air flow meter. While this may straighten air flow to some extent, it does not provide for a uniform velocity profile for the air entering the mass air flow meter. Such a uniform velocity profile is particularly advantageous to improve accuracy of measurement and testing. It is known to provide an air filter with pleats for such a bell mouth. However, such pleats may also not provide an advantageously uniform velocity profile. Further, a bell mouth does not provide for a reduced length for the environmental test chamber. An environmental flow stand inlet flow conditioner in accordance with an embodiment of this invention eliminates these drawbacks.